This invention relates to a method and apparatus for penetrating an existing subterranean formation; and more particularly relates to a method and apparatus for driving a projectile through an existing subterranean formation for enhanced production of coal, petroleum or other solid, gas or liquid substances.
In the recovery of petroleum, gas or liquid substances from subterranean formations, a well bore is formed into the earth and an open hole or cavity is formed beyond the well bore. Once the subterranean formation has been drilled by conventional methods, it is often necessary to stimulate or enhance production. Typically in the past, fluid has been pumped under pressure into the well and into the formation to induce hydraulic fracturing of the formation or by acidizing the well formation with chemical substances to treat or stimulate the formation. Conventional open hole and cased hole completions in combination with fracturing or chemical treatments have severe limitations. These treatments may actually cause the formations to seal up. Further, mediums of low permeability and low porosity are much more difficult to open up with these treatments. Finally, methods involving horizontal drilling applications are extremely difficult, often unsuccessful and can be prohibitively expensive.
There is an unmet need for a method and apparatus for rejuvenating or stimulating an open hole or cavern well in such a way as to substantially increase production rates and overcome the numerous problems and drawbacks inherent in the conventional methods. In particular, it is proposed to employ a novel projectile apparatus which is capable of penetrating a subterranean formation as well as orienting and rotating the projectile within the open hole for discharging the projectile member into the formation.